Over the years, the community of Framingham has changed. In the early 1990s, the need to establish a new group of participants reflecting the increasing diversity of the community was recognized. In 1994, the Omni Cohort 1 of the Framingham Heart Study was enrolled. The original Omni cohort consisted of 506 men and women of African-American, Hispanic, Asian, Indian, Pacific Islander and Native American origins, who at the time of enrollment were residents of Framingham and the surrounding towns. Omni Cohort 1 continues to be examined and followed.

In order to expand from the Omni Cohort 1 and to represent an ethnically diverse group at least 10% of the size of the Gen 3 cohort, enrollment of a second cohort of Omni participants started in 2003 and ended in July 2005. Omni Cohort 2 included many individuals related to the participants of Omni Cohort 1 and also individuals unrelated to Omni Cohort 1 members. The total attendance at the first examination cycle of Omni Cohort 2 included 410 new participants.

Specimens from the two FHS Omni cohorts are now available from recent examination cycles. These samples were collected following the same protocols used for the concurrent Offspring and Third Generation examination. Exam components also follow the same protocols, starting with the first exams of each Omni Cohort. See the exam table below. The FHS encourages the use of Omni specimens in any study whenever necessary covariates are available.